Learn Romanian: Cum a trebuit să studieze mult, băiatul a stat nemâncat și nebăut. - Since he had to study a lot, the boy stayed unfed and without drinking.

They are negative past participles functioning as adjectives to describe a state of deprivation. By adding the prefix ne- to the past participles mâncat (eaten) and băut (drunk), Romanian describes the boy's state directly. Instead of saying he stayed 'without eating', it says he stayed in an 'unfed' state.

Would nemâncat and nebăut change if the subject was a girl?

Yes. Because these negative participles act as adjectives describing the subject, they must agree in gender and number. If the subject were fata (the girl), the endings would change to feminine singular: fata a stat nemâncată și nebăută.

Could we say fără să mănânce instead of using nemâncat?

Yes, a stat fără să mănânce și să bea (he stayed without eating and drinking) is grammatically correct and means the same thing. However, using the ne- prefix with the past participle is a very natural, concise way in Romanian to express an ongoing state of physical deprivation.

Why does the sentence start with Cum? Doesn't that usually mean 'how'?

While cum is the question word for 'how', when it is placed at the beginning of a declarative clause like this, it acts as a conjunction meaning 'since' or 'as'. It sets up the reason for the boy's state: 'Since he had to study a lot...'.